Wednesday, November 30, 2005

Slouching Toward Truth-- Autism and Mercury

David Kirby has partially responded to my long list of questions to him about his use of California Department of Developmental Services data to try to show that reductions in the thimerosal content of vaccines may be responsible for decreasing autism incidence in California. I have shown that the number of California DDS autism cases is growing in California, particularly among young children who are the supposed beneficiaries of reduced thimerosal exposure. Claims that autism incidence is declining are based on a faulty approach to the data—looking at changes in caseload and confusing the change in total caseload with “new cases.

Understandably, Kirby doesn’t seem interested in mucking around in the data with me too extensively, or in answering my detailed questions. But in an e-mail, he did address the key point, and concede that “if the total number of 3-5 year olds in the California DDS system has not declined by 2007, that would deal a severe blow to the autism-thimerosal hypothesis.” He also conceded that total cases among 3-5 year olds, not changes in the rate of increase is the right measure.

Now we’re getting somewhere! Somewhere that’s something like science! We now have agreement from someone highly sympathetic to the hypothesis that thimerosal exposure contributes to autism on a means of falsifying that hypothesis. And we only have to wait two years for the data to come in. I hope the rest of the believers in the theory that thimerosal causes autism will also accept this test of their theory.